1. Field of the Invention
The invention disclosed herein relates to generation, preparation, and administration of pharmaceutical substances, typically intrinsically harmful or toxic pharmaceutical substances such as radioactive pharmaceutical substances, generally known as radiopharmaceuticals to human and animal subjects and, more specifically, to methods and systems and associated components for the generation, preparation, transportation, and administration of fluid radiopharmaceutical substances to human and animal subjects. The non-radiation shielding aspects of the various embodiments presented herein are applicable to all medical fluid applications involving the preparation and delivery/administration of such non-radioactive medical fluids.
2. Description of Related Art
Administration of radioactive pharmaceutical substances or drugs, generally termed radiopharmaceuticals, is often used in the medical field to provide information or imagery of internal body structures and/or functions including, but not limited to, bone, vasculature, organs and organ systems, and other tissue. Additionally, such radiopharmaceuticals may be used as therapeutic agents to kill or inhibit the growth of targeted cells or tissue, such as cancer cells. However, radiopharmaceutical agents used in imaging procedures and therapeutic procedures typically include highly radioactive nuclides of short half-lives and are hazardous to attending medical personnel. These agents are toxic and can have physical and/or chemical effects for attending medical personnel such as clinicians, imaging technicians, nurses, and pharmacists. Excessive radiation exposure is harmful to attending medical personnel due to their occupational repeated exposure to the radiopharmaceuticals. However, due to the short half-life of typical radiopharmaceutical agents and small applied dosages, the radiation exposure risk to benefit ratio for individual patients is acceptable. The constant and repeated exposure of medical personnel to radiopharmaceuticals over an extended period of time is a significant problem in the nuclear medicine field.
A number of techniques are used in the medical field to reduce radiation exposure to attending medical personnel associated with the creation, handling, transport, dose preparation, and administration of radiopharmaceuticals to patients. These techniques encompass one or more of minimizing the time of exposure of medical personnel, maintaining distance between medical personnel and the source of radiation, and/or shielding medical personnel from the source of radiation. As a certain amount of close-proximity interfacing between medical personnel and radiopharmaceutical agents (including patients who have or are to receive radiopharmaceutical agents) is somewhat inevitable during the current practice of generating, preparing, and administering radiopharmaceutical agents to patients and caring for these patients, radiation shielding has considerable importance in the nuclear medicine field. A simple patient radiation guard is disclosed in U.S. Pat. No. 3,984,695 to Collica et al. as an example. It is well-known, for example, to use shielded containers known as “pigs” for general handling and transport of radiopharmaceutical containers (bottles, vials, etc.) and use shielded syringes to remove the radiopharmaceutical from the radiopharmaceutical containers and administer the same to individual patients. Radiopharmaceutical transport pigs are also configured to transport syringes. Examples of shielded transport pigs are disclosed in U.S. Pat. No. 5,274,239 to Lane et al. which is incorporated by reference and U.S. Pat. No. 6,425,174 to Reich, also incorporated herein by reference. An example of a shielded syringe is disclosed in U.S. Pat. No. 4,307,713 to Gaskin et al. which is also incorporated herein by reference. Other shielded syringes are known from U.S. Pat. No. 6,589,158 to Winkler; United States Patent Application Publication No. 2004/0015038 to Lemer; and U.S. Pat. No. 6,162,198 to Coffey et al., all incorporated herein by reference.
As is generally known in the nuclear medicine field, radiation emanates in all directions from radioactive substances and, consequently, emanates in all directions from an unshielded container holding a radioactive substance. While radiation may be scattered or deflected, this effect is generally small enough that it is sufficient to protect personnel from the direct “shine” of radiation and not be too concerned with scattered radiation, unless the activity levels in the container are very high. Transport pigs come in various configurations for holding radiopharmaceutical containers (bottles, vials, syringes, etc.). One form often includes a removable cover that allows access to the held radiopharmaceutical container, as disclosed in United States Patent Application Publication No. 2005/0107698 to Powers et al. incorporated herein by reference. Such containers may be in the form of a vial with an elastomeric, for example, rubber, stopper, or septum which retains the radiopharmaceutical agent in the vial. When the pig cover is in place, the radiation exposure is acceptable. When the cover is opened or removed, a radiation “shine” emanates from the opening. A common sterile transfer procedure to remove the radiopharmaceutical agent from its container is to pierce the elastomeric stopper or septum with a sterile needle on a syringe. Commonly, the exposed surface of the stopper or septum is sterilized with an alcohol wipe prior to piercing the stopper or septum with the transfer needle on the syringe.
Syringes, during loading and once loaded with radiopharmaceutical agents, are commonly handled via syringe shields and shielded glove boxes or containers, but may also be transported in a suitably configured transport pig as noted previously. Syringe shields are commonly hollow cylindrical structures that accommodate the cylindrical body of the syringe and are constructed of lead or tungsten with a lead glass window that allows the handler to view the syringe plunger and liquid volume within the syringe. Due to its cylindrical configuration, syringe shields protect against radiation emissions in a generally radial direction along the length of the syringe body but the two open ends of the syringe shield provide no protection to the handler as there is radiation “shine” emanating from the two ends of the syringe shield. Devices are further known for drawing radiopharmaceutical agents into syringes. For example, U.S. Pat. No. 5,927,351 to Zhu et al. discloses a drawing station for handling radiopharmaceuticals for use in syringes, incorporated herein by reference. In radiopharmaceutical delivery applications, devices are known for remotely administering radioactive substances from syringes to minimize radiation exposures to attending medical personnel as disclosed in U.S. Pat. No. 5,514,071 to Sielaff Jr. et al. or U.S. Pat. No. 3,718,138 to Alexandrov et al. An automated device for controlled administering radioactive substances is disclosed in U.S. Pat. No. 5,472,403 to Cornacchia et al. and is incorporated herein by reference. A system approach to controlling injectors used to inject radioactive material into a patient is disclosed in published German Document No. DE 10 2005 010152.
In addition to the difficulties introduced by the hazardous nature of radiopharmaceuticals, the short half-lives of such radiopharmaceuticals further complicate the administration of a proper dosage to a patient. The radioactivity levels of the radiopharmaceutical agents used as tracers in, for instance, single-photon emission computerized tomography (SPECT) and positron emission tomography (PET) imaging procedures are measured by medical personnel, such as radio-pharmacists or nuclear medicine technologists, to determine the radiation dose that will be administered to the individual during the course of a diagnostic procedure. The radiation dose received depends on a number of factors including the half-life of the radiopharmaceutical agent and the initial radioactivity level of the radiopharmaceutical agent at the time it is injected into the individual. One known solution is to measure or calibrate the initial radioactivity of the radiopharmaceutical and time the injection so that a dose of the desired level of radioactivity is delivered (as calculated from the half-life of the radiopharmaceutical). Often, radiation levels are determined as part of the dispensing or container filling process as disclosed generally in United States Patent Application Publication No. 2006/0151048 to Tochon-Ganguy et al. or measured by a stand-alone device adapted to receive the radiopharmaceutical container as disclosed in U.S. Pat. No. 7,151,267 to Lemer or U.S. Pat. No. 7,105,846 to Eguchi. Radiation detectors have also been placed upon syringe shields and in-line with the radiopharmaceutical delivery system. For example, U.S. Pat. No. 4,401,108 to Gallon et al. discloses a syringe shield for use during drawing, calibration, and injection of radiopharmaceuticals. This syringe shield includes a radiation detector for detecting and calibrating the radioactive dosage of the radiopharmaceutical drawn into the syringe. A similar arrangement to that disclosed by Galkin et al. but in connection with a transport pig is disclosed in Japanese Publication No. JP2005-283431, assigned to Sumitomo Heavy Industries. U.S. Pat. Nos. 4,562,829 and U.S. Pat. No. 4,585,009 to Bergner and Barker et al. respectively, and incorporated herein by reference disclose strontium-rubidium infusion systems and a dosimetry system for use therein. The infusion system includes a generator of the strontium-rubidium radiopharmaceutical in fluid connection with a syringe used to supply pressurized saline. Saline pumped through the strontium-rubidium generator exits the generator either to the patient or to waste collection. Tubing in line between the generator and the patient passes in front of a dosimetry probe to count the number of disintegrations that occur. As the geometric efficiency (or calibration) of the detector, the flow rate through the tubing, and volume of the tubing is known, it is possible to measure the total activity delivered to the patient (for example, in milliCuries). Likewise, radiation measurements have been made upon blood flowing through the patient. For example, U.S. Pat. No. 4,409,966 to Lambrecht et al. discloses shunting of blood flow from a patient through a radiation detector. A significant quantity of information about nuclear medicine imaging devices and procedures can be found in WO 2006/651531 A2 and WO 2007/010534 A2 from Spectrum Dynamics LLC., incorporated herein by reference. A portable fluid delivery unit is known from U.S. Pat. No. 6,773,673 to Layfleld et al., incorporated herein by reference.
As noted above, examples of the use of radiopharmaceutical agents in diagnostic imaging procedures include positron emission tomography (PET) and single-photon emission computerized tomography (SPECT) which are noninvasive, three-dimensional imaging procedures that provide information regarding physiological and biochemical processes in patients. In effect, the radiopharmaceutical agent acts as a tracer to interact with the targeted area. An initial step in producing PET images or SPECT images of for example, vasculature, organs and organ systems, and/or other targeted tissue is to inject the patient with a dose of the radiopharmaceutical agent. The radiopharmaceutical agent is absorbed on or by certain cells in the body structure of interest and concentrates in this area. As an example, fluorodeoxyglucose (FDG) is a slight modification to the normal molecule of glucose, the basic energy fuel of cells, which readily accepts a radionuclide as a replacement to one of the atoms of the molecule. The radiopharmaceutical “tracer” emits a positron which creates photons that can be detected as the tissue is scanned at various angles and the photons pass through a detector array. A computer is used to reconstruct a three-dimensional color tracer image of the selected tissue structure.
With the foregoing background in place, exemplary current practice of generating, preparing, and administration of radiopharmaceuticals will now be described. Typical radiopharmaceutical treatment practice in the United States includes having the radiopharmaceutical agent initially generated off-site from a treatment location, typically a hospital, by an outside nuclear medicine facility and then delivered to the treatment location for further preparation, for example, individual dosing and administration. The treatment location, for example, a hospital, orders specific radioactive substances to be ready at specific time for specific patients. These substances are prepared by the outside nuclear medicine facility and with sufficient radioactivity that they will have the desired radioactivity level at the targeted time. For example, the outside nuclear medicine provider may have a facility equipped with a cyclotron or radioisotope generator in, for example, a lead-shielded enclosure wherein the radiopharmaceutical agent, namely, a radioactive isotope is generated or created. Further refining or dose preparation steps, namely, placing the radioisotope in injectable form, may occur at the off-treatment site. Thus, the outside provider may provide a radiopharmaceutical substance to the treatment site having a desired radioactivity level at the targeted time. Further “individual” dose preparation of the radiopharmaceutical agent may occur at the treatment site. Alternatively, the outside provider may provide a “finished” radiopharmaceutical agent ready for injection to a specified patient at a specified time so that treatment site personnel are only required to confirm that the correct radioactive dosage is present in the radiopharmaceutical agent, for example, in a stand-alone radiation dosimetry device as described previously. During the forgoing process, there is frequent close-proximity contact with radioactive materials by personnel and, as described previously, handling and transport shielding devices are needed for the protection of these personnel.
Transport pigs are commonly employed to transport the radiopharmaceutical agents, which are individual doses prepared for individual patients, to the treatment facility. At the treatment facility, data about each unit dose is entered into a facility computer either manually or through reading a bar code, floppy disk, or other similar data format, which may accompany or be on the transport pig or the radiopharmaceutical agent container. When it is time to deliver a specified unit dose to a specified patient, treatment facility personnel must remove, for example, a syringe containing the radiopharmaceutical agent from the transport pig and confirm that the dose in the syringe is within the range prescribed for that patient. Alternatively, the attending personnel must transfer the radiopharmaceutical agent to a shielded syringe as identified previously and confirm dosage. If the dose is too high, some is discarded into a shielded waste container. If the dose is too low, either a different syringe is used and/or additional agent is loaded into the syringe if available. While it possible for the attending treatment site personnel to be involved with dosage preparation, typical United States practice is to have the radiopharmaceutical agent delivered to the treatment site which will have the desired radioactivity level at the targeted time. Manual manipulation of the radiopharmaceutical agent at the treatment site is limited at the treatment site due to this procedure. Nonetheless, various manual checks are required to confirm that a correct radiopharmaceutical dose is ready for injection into a specific patient. These manual checks include visual inspections and radioactivity measurements as noted above.
As an example of the foregoing, in PET imaging, an injectable radiopharmaceutical agent such as, for instance, FDG (fluorodeoxyglucose) is fabricated in a cyclotron device at an outside nuclear medicine facility. Thereafter, the FDG is processed to be in a radiopharmaceutical form and is transferred in an individual dose container (i.e., vial, bottle, syringe, etc.) and the container loaded into a transport pig to prevent unnecessary radiation exposure to personnel, such as the radio-pharmacist, technician, and driver responsible for creation, handling, and transport of the FDG from the cyclotron site to the PET imaging site. Since the half-life of FDG is short, approximately 110 minutes, it is necessary to quickly transport the FDG to the PET imaging site. Depending upon the elapsed transport time and the initial radioactivity level of the FDG at the time of fabrication, the radioactivity level of the FDG may need to be re-measured at the PET imaging site. As an example, if the radioactivity level is too high, the transport radio-pharmacist of a radio-pharmacist at the PET imaging site may be required to dilute the FDG with a diluent such as, for instance, saline solution, and remove part of the volume or extract fluid to reduce radioactivity prior to patient injection. During this entire process, the handling of FDG from creation to patient injection may be entirely manual. Within this process, shielding products, as described previously (i.e., transport pigs, syringe shields, L-blocks, etc.) are used to shield individuals from FDG. While shielding may reduce the radiation exposure of the radio-pharmacist, the radio-pharmacist may still be exposed to emissions from the radiopharmaceutical agent during the manual mixing, volume reduction, and/or dilution process needed to obtain the required dose. After injection and often after an additional delay to allow the radiopharmaceutical to reach and be absorbed by the desired regions of interest in the body, the patient is typically placed on a moveable bed that slides by remote control into a circular opening of an imaging scanner referred to as the gantry. Positioned around the circular opening and inside the gantry are several rings of radiation detectors. In one type of radiation detector, each detector emits a brief pulse of light every time it is struck with a gamma ray coming from the radionuclide within the patient's body. The pulse of light is amplified by a photomultiplier converted to an electronic signal and the information is sent to the computer that controls the apparatus and records imaging data.
For the sake of completeness, it should be noted that in the United States it also known to have radiopharmaceutical agents delivered in a multi-dose format to the treatment site. As a result, this multi-dose format must be divided into singular doses for individual patients at the treatment site. While it possible that this dividing may occur at the point of injection or administration, it more typical for a radio-pharmacist or nuclear medicine technologist to perform the dividing process in a “hot lab” at the treatment facility. Individual radiopharmaceutical doses are then transported to the administration location within the treatment facility where the doses are administered to specific patients.
In Europe, radiopharmaceutical creation and dose preparation practice differs from United States practice in that these actions typically all occur within a “hot lab” in the treatment facility again, typically, a hospital. As an example, the hospital itself typically has cyclotron or isotope generators (such as technetium generators manufactured by Mallinckrodt Inc., St. Louis, Mo.; Amersham Healthcare, 2636 South Clearbrook Drive, Arlington Heights, Ill. 60005; or GE Healthcare Limited, Amersham Place, Little Chalfont, Buckinghamshire, United Kingdom) in a shielded location in the hot lab. Two manufactures of shielded glove boxes are Comecer in Italy and Lemer Pax in France. Hospital personnel create or extract the radioactive isotope, perform additional chemistry steps necessary to formulate the radioactive drug (i.e., radiopharmaceutical) early in the day, and then prepare unit doses for individual patients, generally close to the time the patient is to be injected with the radiopharmaceutical. While an internal “hot lab” has advantages in minimizing hazardous material transport and improving internal information transfer, additional time and radiation burdens are placed on hospital staff as the measurement of radioactivity levels at the various steps still depends upon manual insertion of a container (i.e., a vial, bottle, or syringe) into a dose calibrator and then repeated adjustments of the radioactivity until the desired level is achieved. The unit dose radiation level is commonly recorded manually or by a printer.
Within the prior art, systems for delivering hazardous fluids are known as disclosed, for example, in U.S. Pat. No. 6,767,319 to Reilly et al. and United States Patent Application Publication No. 2004/0254525 to Uber, III et al., the disclosures of which are incorporated herein by reference. Another system adapted to inject a radioactive liquid into a patient is disclosed in Japanese Publication No. W2000-350783 (see also United States Patent Application Publication No. 2005/0085682 to Sasaki et al.), assigned to Sumitomo Heavy Industries. This published patent application discloses a system which dispenses a volume of radioactive fluid into a coiled “medicine container” situated in a radiation measuring unit. When the prescribed radiation dose is accumulated in the coiled container, another syringe pushes saline through the coiled container and into a patient. A similar device and method is disclosed in Japanese Publication No. JP2002-306609, also assigned to Sumitomo Heavy Industries. Each of the immediately foregoing Japanese publications is incorporated herein by reference.
PCT Application Publication No. WO2004/004787, assigned to Universite Libre De Bruxelles—Hospital Erasme and incorporated herein by reference, discloses a method by which continuous measurement of radioactivity by dosimetry is eliminated. The disclosed method requires an initial calibration step but thereafter, radiation dose is calculated based on the predictable decay of radioactivity as a function of time. Japanese Publication No. JP2004-290455, assigned to Nemoto Kyorindo KK, discloses a radiation-shielded injector system which withdraws FDG from prefilled syringes and allows other fluids such as saline to be administered. European Application Publication No. EP 1616587, assigned to University of Zurich and incorporated herein by reference, discloses a radioactive fluid dispensing device that pushes FDG into tubing within a radiation dose calibrator prior to a saline injection that administers the FDG to the patient. United States Patent Application Publication Nos. 2005/0203329 and 2005/0203330 to Mute et al. disclose a robotic, automated system for extracting radioactive fluids from a vial or bulk container into a number of unit dose syringes. This system may have application in a hospital pharmacy setting. United States Patent Application Publication No. 2005/0277833, assigned to E-Z-EM, Inc. and incorporated herein by reference, discloses an injection system for handling, mixing, dispensing, and/or injecting mixtures of pharmaceutical agents. Radiation dose is monitored by discrete detectors at several locations in the apparatus.